This invention relates to smoothing and cleaning of molded ceramics, such as clay and the like.
In the manufacture of ceramic articles such as cups, vases and the like, the article is often first formed in a mold from soft material. After release from the mold, the article is permitted to partially harden, is then smoothed and cleaned, and is finally fired in a kiln.
Smoothing and cleaning is necessary to remove the mold seam as well as any rough spots which usually occur upon molding of items of this type. In addition, it may be desired to round sharp corners such as may be present at the rim of a drinking cup. All of this must be done while the ceramic article is only semi-hard and prior to firing in a kiln.
Heretofore, when such smoothing and cleaning has been performed by hand, the worker has usually held an abrasive pad in his hand and pressed the pad against the semi-hard ceramic article with his fingers and then rubbed back and forth on the article. Unfortunately, most workers do not have adequate control of finger pressure in such an operation. It has been found that the relatively high pressure in pounds per square inch applied by the finger tips through the abrasive pad may cause the article to break.
Tools to assist in manual cleaning of objects have of course long been known. The above-identified patents disclose several types of such tools.
U.S. Pat. No 1,660,351 discloses a hand tool for holding a cleaning sponge for fabrics, but the tool includes a rigid backing plate and spring arms extending into the sponge. If such a tool was utilized to smooth and clean semi-hard ceramic articles, the sponge would have to be compressed substantially to provide sufficient pressure, causing the spring arms to interfere with the smoothing operation. Furthermore, the rigid backing plate would be apt to cause excessive pressure to be applied to the ceramic article and thereby cause breakage thereof, just as in the case of finger tips.
U.S. Pat. No. 2,529,434 discloses a holder for shredded metal, with the tool having spring metal arms supporting the shredded metal. However, the arms and especially the central mounting arrangement would also cause undue pressure to be applied to a semi-hard ceramic article if the worker did not have perfect hand pressure control. There would still be substantial danger of article breakage.
U.S. Pat. No. 4,071,983 discloses a cleaning pad holder for griddles, which would imply the usage of high pressure. This holder also has extensive backing means for the pad to enable sufficient pressure to be applied to remove baked-on material from a griddle. If used for smoothing and cleaning semi-hard ceramic articles, the danger of article breakage would be very high.
The present invention substantially reduces the aforementioned problem of breakage and provides a simple yet unique hand tool for smoothing and cleaning of molded ceramic articles.
In accordance with the various aspects of the inventive concept, the tool comprises an elongated main body of spring wire having reverse bends at its ends to form a pair of spaced opposed springable legs which are normally parallel to the main tool body. Fastening devices are mounted on the leg ends for securely attaching to the opposite ends of a flexible elongated abrasive cleaning pad which is freely suspended therebetween in a taut condition and which is substantially spaced from and parallel to the main tool body. When the tool is held in the hand and the pad rubbed against the ceramic article for smoothing and cleaning, the tool legs as well as the fastening devices and pad ends springingly move toward the main tool body in an amount depending upon the extent of pressure applied. The direct pressure applied to the freely suspended pad is thus absorbed by the springable legs through the fastening devices.